This invention relates to a circuit arrangement for generating a direct voltage from a sinusoidal input voltage for at least a control circuit, comprising a rectifier whose output is coupled to a smoothing capacitor arranged in parallel with the control circuit, and comprising a load which is arranged between the two output terminals of the rectifier.
A circuit arrangement of this type is known from U.S. Pat. No. 4,766,350, which issued on 8/23/88/. In this circuit arrangement a sinusoidal input voltage is applied to a rectifier whose rectified output voltage is applied to a load which is a gas or vapour discharge lamp including the required circuit elements. The sinusoidal input voltage is also applied to a second rectifier which has a first capacitor connected to its first input terminal and a second capacitor connected to its second input terminal. A parallel arrangement of a smoothing capacitor and a control circuit for operating a circuit arrangement including a gas or vapour discharge lamp is connected to the output of the second rectifier.
The capacitive voltage divider constituted by the first and second capacitors and the smoothing capacitor generates the voltage required for the supply of the control circuit. Since the negative reference points of the two rectifiers are interconnected via a capacitor, the potential at the negative reference point of the second rectifier fluctuates. It has been found that this results in distortions of the input current for the circuit arrangement, which distortions exert a load on the mains supplying the sinusoidal input voltage.